You must be talking about loose tea not individually wrapped in 7g packets? I use my wine cooler to store Japanese greens. It cools through a different process than a condenser so there's no humidity. Other than that, try to store in a cool dark place as well sealed as possible, and drink within 6 months.

Cool basement? Cabinet low to the ground? Lots of options. The most important thing is to make sure you're storing the tea in an airtight container. A good ziplock style foil pouch should do the trick.

Currently I have a 250 gram pack of Imperial TGY from YS, they are in individual 7 gram vacum sealed bags, they keep fresh for a year, just keep it at a constant temperature, I keep it in my cupboard, it is dry, cool, the temperature never goes above 25 C, so it is no problem, no need to buy a wine cooler, I would only buy a wine cooler for japanese greens, but I rarely order more than I can consume in a months time.

How much it lasts would only matter if I owned a teavendor, because no tea drinker would buy a 2 year old green oolong, everybody wants fresh tea, so I would go out of business if I sold 2011 TGY in 2013. As far as I am concerned I can consume all my tea before that time, I usually need a kilo of green oolong for a year, and only buy ahead for max 2 months.

After removing from a vacuum pack you'd want the tea to acclimate for a while. I generally find that if I dump it into a tin, then about the third time making some is the best -- i.e., after opening the tin a few times with a day or so in between.

If there's any discernible roast, then the tea will go through changes for the first year, and will be better after it has settled.

Also, no vacuum sealer creates 100% vacuum, but some are better than others. If I remember right, the typical home sealer gets about 70% vacuum, and more commercial ones get somewhere between 80%-90%. (That's why some put oxygen absorbers in the package.) So how long a tea stays fresh in a vacuum pack will depend partially on how complete the vacuum is.

Regarding bags vs tins, I don't trust bags because I don't always seal them completely, and I've also had the zip seal separate from the bag and I didn't realize it until it had been like that for some weeks (or longer). However, you can reduce the amount of air in a bag before sealing it, which you obviously can't do with a tin.